Abstract:Superconductivity in the simple elements is of both technological relevance and fundamental scientific interest in the investigation of superconductivity phenomena. Recent advances in the instrumentation of physics under pressure have enabled the observation of superconductivity in many elements not previously known to superconduct, and at steadily increasing temperatures. This article offers a review of the state of the art in the superconductivity of elements, highlighting underlying correlations and general… Show more
“…In fact it is actually a composite intermetallic formed by a multilayer of first planes of a bulk low T c superconductor, boron that shows T c =11K under pressure [14]: graphene B monolayers, intercalated by second metallic planes of a non superconducting element, magnesium [14]: hcp Mg monolayers. Therefore following the discovery of Nagamatsu et al [13] it was first proposed by the Rome group [15][16][17] that MgB 2 shows mutigap superconductivity.…”
The thermal lattice expansion in the superconducting Mg 1-x Al x B 2 system (x=0, 0.13 and 0.59) has been measured using high-resolution X-ray powder diffraction. An unusual large negative
“…In fact it is actually a composite intermetallic formed by a multilayer of first planes of a bulk low T c superconductor, boron that shows T c =11K under pressure [14]: graphene B monolayers, intercalated by second metallic planes of a non superconducting element, magnesium [14]: hcp Mg monolayers. Therefore following the discovery of Nagamatsu et al [13] it was first proposed by the Rome group [15][16][17] that MgB 2 shows mutigap superconductivity.…”
The thermal lattice expansion in the superconducting Mg 1-x Al x B 2 system (x=0, 0.13 and 0.59) has been measured using high-resolution X-ray powder diffraction. An unusual large negative
“…As metallicity is a necessary condition for superconductivity, generally becomes more likely under pressure [1,2]. Wigner and Huntington [3], already in 1935 suggested the possibility of a metallic modification of hydrogen under very high pressures.…”
Abstract. Due to its low atomic mass, hydrogen is the most promising element to search for hightemperature phononic superconductors. However, metallic phases of hydrogen are only expected at extreme pressures (400 GPa or higher). (2015)], shows that metallization of hydrogen can be reached at significantly lower pressure by inserting it in the matrix of other elements. In this work we investigate the phase diagram and the superconducting properties of the H-S systems by means of minima hopping method for structure prediction and density functional theory for superconductors. We also show that Se-H has a similar phase diagram as its sulfur counterpart as well as high superconducting critical temperature. We predict H3Se to exceed 120 K superconductivity at 100 GPa. We show that both H3Se and H3S, due to the critical temperature and peculiar electronic structure, present rather unusual superconducting properties.Under high pressure conditions, insulating and semiconducting materials tend to become metallic, because, with increasing electronic density, the kinetic energy grows faster than the potential energy. As metallicity is a necessary condition for superconductivity, generally becomes more likely under pressure [1,2]. Wigner and Huntington [3], already in 1935 suggested the possibility of a metallic modification of hydrogen under very high pressures. Ashcroft and Richardson predicted [4,5] hydrogen to become metallic under pressure and also the possibility to be a high temperature superconductor. The high critical temperature (T C ) of hydrogen [6-8] is a consequence of its low atomic mass leading to high energy vibrational modes and in turn to a large phase space available for electronphonon scattering to induce superconductivity [9]. However, the estimated metallization pressure [10,11] is beyond the current experimental capabilities [12][13][14][15]. It was only recently that hydrogen-rich compounds (chemically pre-compressed) started to be explored as a way to decrease the tremendous metallization pressure of pure hydrogen [16]. The first system explored experimentally was silane (SiH 4 ) [17]. Soon after, many others materials have been explored experimentally [18][19][20][21] and theoretically [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].
“…1. In this approximation, one introduces the DOS for one spin ̺ 1 (ǫ) in (10) and assumes that it is constant around the Fermi surface. This is strictly true in 2D and otherwise a good approximation in any D provided that ω D /E F ≪ 1.…”
Section: Cooper Pairing In One Dimensionmentioning
We study electron pairing in a one-dimensional (1D) fermion gas at zero temperature under zero-and finite-range, attractive, two-body interactions. The binding energy of Cooper pairs (CPs) with zero total or center-of-mass momentum (CMM) increases with attraction strength and decreases with interaction range for fixed strength. The excitation energy of 1D CPs with nonzero CMM display novel, unique properties. It satisfies a dispersion relation with two branches: a phonon-like linear excitation for small CP CMM; this is followed by roton-like quadratic excitation minimum for CMM greater than twice the Fermi wavenumber, but only above a minimum threshold attraction strength. The expected quadratic-in-CMM dispersion in vacuo when the Fermi wavenumber is set to zero is recovered for any coupling. This paper completes a three-part exploration initiated in 2D and continued in 3D.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.